Aromatic diimides of 3,5-dialkyl-4-hydroxyphenylsubstituted amines

ABSTRACT

Aromatic diimides of 3,5-dialkyl-4-hydroxyphenylsubstituted amines of this invention effectively stabilize organic polymeric materials against the effects of heat and oxygen. The diimides of this invention are prepared by reacting the appropriate 3,5dialkyl-4-hydroxyphenylsubstituted amine with an aromatic dianhydride or aromatic diimide. An example of this class of stabilizer is N,N&#39;&#39;-bis(3,5-di-t-butyl-4-hydroxybenzyl)diphenyl sulfone-3,4,3&#39;&#39;,4&#39;&#39;-tetracarboxylic acid diimide.

1 AROMATIC DIIMIDES OF 3,5-DlALKYL-4-HYDROXYPHENYLSUB- STITUTED AMINES [75] Inventor: John F. Stephen, New City, NY. [73] Assignee: Ciba-Geigy Corporation, Ardsley,

[22] Filed: Jan. 18, 1973 [21] Appl. No.: 324,629

Related US. Application Data [62] Division of Ser. No. 186,463, Oct. 4, 1971, Pat. No.

[52] US. Cl 260/453 N, 260/4585 S [51] Int. Cl.-.... C08f 45/58 [58] Field of Search 260/458 N, 45.85 S

[56] References Cited UNITED STATES PATENTS 3,734,926 5/1973 Dexter 260/458 N 11] 1 3,821,161 June 28, 1974 3,746,721 7/1973 Stephen 260/458 N Primary ExamineF-Melvyn I. Marquis [57] ABSTRACT Aromatic diimides of 3,5-dia1kyl-4-hydroxyphenylsubstituted amines of this invention effectively stabilize organic polymeric materials against theeffects of heat and oxygen. The diimides of this invention are prepared by reacting the appropriate 3,5-dia1kyl-4- hydroxyphenylsubstituted amine with an aromatic dianhydride or aromatic diimide. An exampleof this class of stabilizer isN,N-bis(3,5-di-t-butyl-4-hydroxybenzyl )diphenyl su1fone-3 ,4,3 ,4 -te tracarboxylic acid diimide. i

7 Claims, N0 Drawings 1 AROMATIC n nvnnns or 3,5-i)IALKYLJ HYDFGYYFEENYLSTJBSTITUTED AMINES This application is a divisional application of U.S. application Ser. No. 186,463, filed on Oct. 4, 1971, now U.S. Pat. No. 3,746,721.

DETAILED DESCRIPTION one to four carbon atoms which are represented by R as dichlorobenzene at reflux temperatures.

and R are methyl, ethyl, propyl, isopropyl, butyl and t-butyl. The preferred groups are methyl, isopropyh and the tertiary alkyl, t-butyl.

The compounds of the formula wherein y is'O, 2 and 3, can be prepared by reacting a 3,5-dialkyl-4-hydroxyphenylsubstituted amine of the formula:

H O (C yHZy) NH2 wherein R and R are as defined previously, with ari aromatic dianhydride of the formula:

0. III

The compounds of formula 1 wherein y is 1 can be prepared by reacting 3,5dialkyl-4-hydroxybenzyl dialkylsubstituted amine of the formula:

2 wherein R and R are as defined previously and R is 7 alkyl such as methyl or ethyl with an aromatic diimide of the formula:

wherein X is as defined above, in an inert solvent such as dimethyl formamide at approximately 120C.

wherein y is 0 can be prepared as described in U.S. Pat.

No. 3,198,797. The amine, when y is 2 can be prepared, for example, through chloromethylation of a dialkylphenol as described in U.S. Pat. No. 2,838,571, followed by treatment with sodium or potassium cyanide and reduction of the resultant dialkylhydroxyphenyl acetonitrile to the amine. The amine wherein y is 3 can be prepared by reducing 3,5-dialky1-4-hydroxyphenylpropionitrile with lithium aluminum hydride to yield the corresponding amine. The nitrile can be prepared according to the method described in U.S. Pat. ,No. 3,121,732 wherein the appropriate dialkylphenol is reacted with acrylonitrile. The 3,5-dialkyl-4- hydroxybenzyl dialkyl amine of formula IV can be prepared as described by E. P. Previc, et al., Industrial and Engineering Chemistry, Vol. 53, N0. 6, Page 469, June The intermediate aromatic dianhydrides and diimides can be prepared as follows:

, a. The diphenyl ether-3,4,3, 4',-tetracarboxylic acid dianhydride is prepared by first preparing the corresponding tetracarboxylic acid as described by Marvel and Rassweiler, .1. AM. CHEM. SOC., 80, l 196(1958), followed by treatment of the tetra acid with acetic anhydride. The diphenyl ether-3,4,3',4,-tetracarboxylic acid diimide is prepared by decomposing the tetraammonium salt of diphenyl ether-3,4,3,

' 4'-tetracarboxylic acid at 250 280C as described by 3 v c. The diphenyl methane-3,4,3,4-tetracarboxylic acid dianhydride is prepared by first preparing diphenyl methane-3,4,3',4,-tetracarboxylic acid by the catalytic reduction of 3,4,3',4'-tetracarbomethoxybenzophenone to the corresponding diphenyl methane ester followed by hydrolysis to the desired tetra acid as described in U.S. Pat. No. 3,332,964. This is followed by treatment of the corresponding tetra acid with acetic anhydride. The diphenyl methane-3,4,3,4- tetracarboxylic acid diimide is prepared by decompos ing the tetraammonium salt of the corresponding tetraacid as described in U.S. Pat. No. 3,275,651.

d. The 4,4'-isopropylidene diphthalic acid dianhydride is prepared from the corresponding tetraacid by the oxidation of 2,2-bis(3,4-dimethylphenyl)propane by the method described in U.S. Pat. No. 2,712,543.

The tetraacid is converted to the corresponding dianhydride as described in U.S. Pat. No. 2,712,543. The

4,4'-isopropylidene diphthalic acid diimide can be prepared according to the method used to prepare the corresponding diphenyl methane derivative namely, U.S. Pat.No. 3,275,65

The compounds of this invention are stabilizers of organic polymeric material normally subject to thermal and oxidative deterioration. Materials which are thus stabilized include synthetic organic polymeric substances such as vinyl resins formed from the polymerization of vinyl halides or from the copolymerization of vinyl halides with unsaturated polymerizable compounds, e.g., vinylesters, a,B-unsaturated ketones, a.B-unsaturated aldehydes, and unsaturated hydrocarbons such as butadienes and styrene; poly-a-olefins such as polyethylene, polypropylene. polybutylenc, and the like. including copolymers of poly-a-olefins; polyurethanes and polyamides such as polyhexamethylene adipamide and polycaprolactam; polyesters such as polyethylene terephthalates; polycarbonates; polyacetals; polystyrene; polyethyleneoxide; polyisoprene, polybutadene; and copolymers such as those of high impact polystyrene containing copolymers of butadiene and styrene and those formed by the copolymerization of acrylonitrile, butadiene and/or styrene.

In general, one or more of the stabilizers of the present invention are employed in amounts, in toto, of from about 0.005 to about 5 percent by weight of the composition to be stabilized. A particularly advantageous range of the present stabilizers is from about 0.05 percent to about 2 percent. The preferred range is particularly effective in polyolefins such as polypropylene and polyethylene. 1

These compounds may be incorporated in the poly- I mer substance during the usual processing operations, for example, by hot-milling, the composition then being extruded, pressed, roll-molded or the like into films, fibers, filaments, hollowspheres and the like. The heat stabilizing properties of these compounds advantageously stabilize the polymer against degradation during such processing at the high temperatures generally encountered.

The stabilizers employed in this invention can also be used in combination with other stabilizers or additives. Especially useful co-stabilizers are dilauryl-B-thiodipropionate and distearyl-,B-thiodipropionate.

The following formula represents co-stabilizers which are in certain instances very useful in combination with the stabilizers of this invention:

wherein R is an alkyl group having from six to 24 carbon atoms; and m is an integer from 1 to 6. The above co-stabilizers are used in the amount of from 0.01 to 2 percent by weight of the organic material, and preferably from 0.1 to 1 percent.

Other antioxidants, antiozonants, thermal stabilizers, ultraviolet light absorbers, coloring materials, dyes, pigments, metal chelating agents, etc., may also be used in the compositions in combination with the stabilizers of the invention.

The following are presented to further illustrate the present invention without introducing any limitation thereto.

EXAMPLE 1 lization from ethanol-benzene mixture gave material, I

melting point 187l89.

Analysis for C ,,H N O Calculated: C, 74.17; H, 7.04; N, 3.76 Found: C, 74.09; H, 7.25; N, 3.72

EXAMPLE 2 By essentially following the procedure of Example 1,

but substituting for the diphenylether tetracarboxylic acid diimide the following aromatic diimides:

a. diphenylsulfone-3,4,3,4'-tetracarboxylic acid diimide b. diphenylmethane-3,4,3,3'tetracarboxylic acid diimide c. 4,4-isopropy1idene diphthalic acid diimide There is respectively obtained:

a. N ,N-bis(3,5-di-t-butyl-4-hydroxybenzyl) diphenylsulfone-3,4,3,4-tetracarboxylic acid diimide b. N,N'-bis(3,5-di-t-butyl-4-hydroxybenzyl) diphenylmethane-3,4,3',4-tetracarboxylic acid diimide c. v N,N'-bis(3,5-di-t-butyl4-hydroxybenzyl)-4,4'- isopropylidene diphthalic acid diimide EXAMPLE 3 and washed with petroleum ether. The filtrate is dried and recrystallized from aqueous acetone, and dried.

b. By substituting an equivalent amount of 2-(3,5-dit-butyl-4-hydroxyphenyl)ethylamine for 3,5-di-t-butyl- '4-hydroxyphenylamine in the above procedure, the

EXAMPLE 4 By essentially following the procedure of Example 3 and substituting for the diphenylsulfone-3,4,3',4- tetracarboxylic acid 'dianhydride in parts (a), (b) and (c) an equivalent amount of the following dianhydrides:

l. diphenylmethane-3,4,3,4-tetracarboxylic acid dianhydride 2. diphenylether-3,4,3, 4'-tetracarboxylic acid dianhydride there is obtained the following diimides:

a. N,N'-bis(3,5-di-t-butyl-4-hydroxyphenyl) diphenylmethane-3,4,3',4'-tetracarboxylic acid diimide b. N ,N-bis[ 2-( 3 ,5 -di-t-butyl-4-hydroxyphenyl) ethyl] diphenylmethane-3,4,3,4-tetracarboxylic acid diimide c. N,N'-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propyl] diphenylmethane-3,4,3',4-tetracarboxylic acid diimide I a. N,N'-bis(3,5-di-t-butyl-4-hydroxyphenyl) diphenylether-3,4,3',4-tetracarboxylic acid diimide b. N ,N-bis[ 2-( 3 ,5 -di-tbutyl-4-hydroxyphenyl) ethyl] diphenylether-3,4,3',4'-tetracarboxylic acid diimide c. N,N-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl) propyl] diphenylether-3,4,3,4-tetracarboxylic acid diimide EXAMPLE 5 Unstabilized polypropylene powder (Hercules Profax 6501 is thoroughly blended with 0.2 percent by weight of N,N'-bis( 3,5-di-t-butylhydroxybenzyl)diphenylsulfone-3,4,3,4- tetracarboxylic diimide.

Also prepared are samples of polypropylene containing 0.1 percent by weight ofthe same stabilizer and 0.3 percent by weight of distearylthiodipropionate (DSTD- P). The blended materials are milled on a two-roll mill at 182C for minutes, after which time the stabilized polypropylene is sheeted from the mill and allowed to cool.

The milled polypropylene sheets are cut into pieces and pressed for 7 minutes on a hydraulic press at 218C, 500 pounds per square inch pressure. The resulting sheets of 25 mil thickness are tested for resistance to accelerated aging in a forced draft oven at 150C for 100 hours. 1

The stabilized polypropylene has better color retention, physical integrity and less weight loss after oven aging than polypropylene which 'is unstabilized.

' Stabilized polypropylene compositions are also obtained when 0.5 percent of N,N'-bis(3,5-di-t-butyl-4- hydroxyphenylpropyl)diphenylmethane-3,4,3,4- tetracarboxylic acid diimide and N,N-bis(3-me'thyl-5- t-butyl-4-hydroxybenzyl)diphenylsulfone-3,4,3',4'- tetracarboxylic acid diimide respectively are employed alone or in combination with DSTDP.

EXAMPLE 6 To 39.3 g (0.15 moles)of hexamethylene diammonium adipate is added 0.177 g (7.5 X -l0 mole; 0.5 mole percent) of hexamethylene diammonium diacetate as molecular weight control agent, and 0.183 g (0.5 percent of theoretical nylon yield) of N,N'-bis[2- (3 ,5-di-t-butyl-4- hydroxyphenyl)ethyl]diphenylsulfone-3,4,3,4- tetracarboxylic acid diimide. The mixture is blended thoroughly and added to a Pyrex polymer tube.

The polymer is evacuated three times and each time filled with high purity nitrogen. The polymer tube with the continuously maintained, slightly positive nitrogen pressure, is placed in a methyl salicylate vapor bath at 220 C. After one hour at 220C the polymer tube is transferred to an o-phenyl-phenol bath at 285 C for one hour. The polymer tube is kept in the 285 C vapor bath for an additional one-half hour while it is maintained under vacuum of less than 1 mm pressure. High purity nitrogen is then readmitted and the polymer tube is allowed to cool.

The nylon-6,6 obtained is ground in a mill at ambient temperature of 25C. About 2 g are heated in a small glass Petridish in a circulating air-rotary oven at 140C for 65 hours. The viscosity of a 1 percent sulfuric acid solution of aged and unaged polymer samples are determined at 25C. Stabilizer effectiveness is judged by the percent retention of specific viscosity, colorformation, and weight retention after oven aging. The stabilized polyamide has better viscosity, color retention and substantially less weight loss after oven aging than a polyamide which is unstabilized.

Stabilized polyamide compositions are prepared in a similar manner as above with the following stabilizers:

a. 0.5 percent of N,N-bis(3,5-di-t-butyl-4- hydroxybenzyl)diphenylether-3,4,3,4-tetracarboxy|ic acid diimide b. 0.5 percent of N,N'-bis(3-methyl-5-t-butyl-4- hydroxybenzyl)diphenylsulfone-3,4,3,4'- tetracarboxylic acid diimide c. 0.5 percent of N,N-bis[2-(3,5-di-t-butyl-4- hydroxyphenyl)ethyl]diphenylsulfone-3,4,3,4'- tetracarboxylic acid diimide d. 0.5 percent of N,N-bis[3-(3,5-di-t-butyl-4- hydroxyphenyl)propylldiphenylmethane-B,4,3',4'- tetracarboxylic acid diimide Substantially similar results are obtained when 0.5 percent of the aforementioned stabilizers are incorporated into nylon-6,6 flakes before extrusion.

EXAMPLE 7 A quantity of SBR emulsion containing g of rubber (500 ml of cold SBR type 1500) previously stored under nitrogen, is placed in a beaker and stirred vigorously. The pH of the emulsion is adjusted to 10.5 with a 0.5N NaOH solution.

To the emulsion is added 50 ml of 25 percentNaCl solution. A 6,percent NaCl solution which has been Y acidified with HCl to a pH 1.5 is added in a thin stream through cheese cloth, and rinsed with distilled water.

After three subsequent washings with fresh distilled water, the coagulated rubber is dried, first at mm Hg and finally to constant weight under high vacuum 1 mm.) at 45C.

The dried rubber (25 g) is heated under nitrogen at 125 in a Brabender mixer and to this is added with mixing 0.125 g (0.5 percent) of N,N'-bis(3,5-di-t butyl-4-hydroxybenzyl)diphenylsulfone-3,4,3',4- tetracarboxylic acid diimide. The composition is mixed for 5 minutes after which it is cooled and compression molded at 125C into 5 inches X 5 inches X 0.025 inch plaques.

Similar results are obtained with N,N'-bis(3,5-di-tbutyl-4-hydroxybenzyl)diphenylmethane-3,4,3',4- tetracarboxylic acid diimide N,N -bis[3,5-di-t-butyl-4- hydroxyphenyhpropyl]diphenylether-3,4,3,4- tetracarboxylic acid diimide are used in place of the above mentioned stabilizer in the rubber composition.

EXAMPLE 8 A composition is prepared comprising linear polyethylene and 1.0 percent by weight of N,N'-bis(3,5-di-tbutyl-4-hydroxybenzyl)-4,4'-isopropylidine diphthalic acid diimide. This composition resists discoloration at C longer than one which does not contain the stabilizer.

What is claimedis:

l. A composition of matter stabilized against oxidative deterioration which comprises an organic poly meric material normally subject to oxidative deterioration containing from 0.005 to 5 percent by weight of a stabilizing compound of the formula wherein each of R and R is the same or different lower alkyl group of from one to four carbon atoms;

X is selected from the group consisting of 0, S0 and alkylene of from one to three carbon atoms; and

y has a value of from 0 to 3.

2. The composition of claim 1 wherein R and R is tertiary butyl or methyl.

3. The composition of claim 2 wherein the stabilizing compound is N,N'-bis-(3,5-di-t-butyl-4-hydroxybenzyl)4,4-isopropylidene diphthalic acid diimide.

4. The composition of claim 2 wherein the stabilizing compound is N,N'-bis-(3,5-di-t-butyl-4- hydroxybenzyl)diphenylsulfone-3,4,3,4- tetracarboxylic acid diimide.

5. The composition of claim 2 wherein the stabilizing compound is N,N'-bis-(3,5-di-t-butyl-4- hydroxybenzyl)diphenylether-3,4,3',4'-tetracarboxylic acid diimide.

6. The composition of claim 2 wherein the stabilizing compound is N,N-bis(3,5-di-t-butyl-4- hydroxybenzyl)diphenylmethane-3,4,3,4- tetracarboxylic acid diimide.

7. The composition of claim 2 wherein the stabilizing compound is N,N'-bis(3-methyl-5-t-buty1-4- hydroxybenzyl)diphenylether 3,4,3',4-tetracarboxylic acid diimide. 

2. The composition of claim 1 wherein R1 and R2 is tertiary butyl or methyl.
 3. The composition of claim 2 wherein the stabilizing compound is N,N''-bis-(3,5-di-t-butyl-4-hydroxybenzyl)4,4''-isopropylidene diphthalic acid diimide.
 4. The composition of claim 2 wherein the stabilizing compound is N,N''-bis-(3,5-di-t-butyl-4-hydroxybenzyl)diphenylsulfone-3,4, 3'',4''-tetracarboxylic acid diimide.
 5. The composition of claim 2 wherein the stabilizing compound is N,N''-bis-(3,5-di-t-butyl-4-hydroxybenzyl)diphenylether-3,4,3'', 4''-tetracarboxylic acid diimide.
 6. The composition of claim 2 wherein the stabilizing compound is N,N''-bis(3,5-di-t-butyl-4-hydroxybenzyl)diphenylmethane-3,4, 3'',4''-tetracarboxylic acid diimide.
 7. The composition of claim 2 wherein the stabilizing compound is N,N''-bis(3-methyl-5-t-butyl-4-hydroxybenzyl)diphenylether 3,4, 3'',4''-tetracarboxylic acid diimide. 